A more powerful battery

So are there any other batteries I could buy that are more powerful or will last longer then the one that comes with the eris? Because I have tried numerous things to save my battery but yet it still won't last till the end of the day. And now I'm to the point where I would just buy a new battery, so are there any other batteries I could buy for the eris that are more powerful?

I got one of the Seidio 1750mAh extended life batteries on Amazon for $41 with free shipping. (If you go there, be sure you get the $41 price. You can also pay $53 for the same battery if you want to or you're not careful which links you click...)

I'm amazed by this battery. The mAh numbers don't imply it, but I easily get twice the life of the original HTC battery. Before I got this, I'd be compulsively plugging my phone into a charger everywhere I went. Now I can go a whole day with light use. If I use the phone a lot, I usually top it off in the afternoon before I leave work.